The contest, which ran in May, sought talented YouTube users to submit 30-second videos featuring ozone — an invisible gas formed when vehicle exhaust or other emissions mix with sunlight and heat. The rules were to show how ozone is formed, how it impacts health, or what people can do to prevent it.

More than 500 people scored their favorites from the five finalists.

The winners received cash prizes, while all the qualified participants' videos will be used for educational purposes.